Screen unit

ABSTRACT

A screen unit includes: a first frame and a second frame which extend in parallel with each other; a first roll provided in the first frame in such a manner as to be freely rotatable and having an urging force in the winding direction of the first roll; a second roll provided in the second frame in such a manner as to be freely rotatable and having an urging force in the winding direction of the second roll; and a screen which has one end fixed to the first roll and the other end fixed to the second roll, and is wound around the first roll and the second roll by the urging forces.

The entire disclosure of Japanese Patent Application No. 2010-197436, filed on Sep. 3, 2010, is expressly incorporated by reference herein.

BACKGROUND

1. Technical Field

The present invention relates to a screen unit.

2. Related Art

A screen unit which reflects projection light emitted from a projection type display apparatus such as a projector and displays an image of the projection light is known. JP-A-11-142974 discloses a portable screen which has a first frame to which a spring roll is attached in such a manner as to be freely rotatable, and a second frame to which one end of the screen wound around the spring roll is fixed. An expanding unit is attached to the first and second frames. The first and second frames are supported by a plurality of support feet substantially in the vertical direction during use. For storing the screen, either the first frame or the second frame is pushed toward the other frame, whereby the screen is wound around the spring roll with the expanding unit folded.

According to this screen unit in the related art, a slight allowance is provided for an inclination (twist) of the screen in the extending direction of the spring roll since the spring roll is movable to a certain extent in its extending direction. However, when the twist exceeds the allowance, the screen is wound with the twist at the time of storage. In this case, the twist produces distortion or wrinkle on the screen when the stored screen with the twist is again expanded.

Therefore, such a screen unit which is compact and can reduce distortion and wrinkle produced on the surface of a screen during use by decreasing twist of the screen at the time of storage has been demanded.

SUMMARY

An advantage of some aspects of the invention is to provide a technology capable of solving at least a part of the aforementioned problems, and the invention can be implemented as the following forms or application examples.

Application Example 1

This application example of the invention is directed to a screen unit including: a first frame and a second frame which extend in parallel with each other; a first roll provided in the first frame in such a manner as to be freely rotatable and having an urging force in the winding direction of the first roll; a second roll provided in the second frame in such a manner as to be freely rotatable and having an urging force in the winding direction of the second roll; and a screen which has one end fixed to the first roll and the other end fixed to the second roll, and is wound around the first roll and the second roll by the urging forces.

According to this screen unit, the first roll to which the one end of the screen is fixed has the urging force in the winding direction of the first roll, and the second roll to which the other end of the screen is fixed has the urging force in the winding direction of the second roll. In this case, the first roll and the second roll can produce mutual corrections by urging the screen toward both the ends thereof at the time of winding of the screen. Thus, twist produced when the screen is stored (wound or wound around) decreases, which reduces distortion or wrinkle produced on the surface of the screen of the screen unit during use.

Application Example 2

In the screen unit of the application example of the invention, it is preferable that the urging force of the first roll is different from the urging force of the second roll.

According to this configuration, the urging force of the first roll is different from the urging force of the second roll. In this case, the roll having the small urging force follows the rotation of the roll having the large urging force when the screen is wound. When the roll having the small urging force winds the screen while following the rotation of the roll having the large urging force and rotating to wind the screen, the two rolls produce mutual corrections. Thus, twist produced when the screen is wound can be further reduced.

Application Example 3

In the screen unit of the application example of the invention, it is preferable that the strength ratio of the urging force of the first roll to the urging force of the second roll is set at approximately 9:1.

According to this configuration, the strength ratio of the urging force of the first roll to the urging force of the second roll is set at approximately 9:1. In this case, a preferable strength relationship can be established, which further reduces twist on the screen produced when the screen is wound.

Application Example 4

In the screen unit of the application example of the invention, it is preferable that the roll diameter of the first roll is different from the roll diameter of the second roll.

According to this configuration, the roll diameters of the first roll and the second roll are different from each other. In this case, size reduction of the screen unit can be achieved by storing a component of the screen unit within the frame in which the roll having the smaller roll diameter is disposed (first frame or second frame). The component stored in the frame is an expanding unit for urging the first frame and the second frame in directions away from each other, for example.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be described with reference to the accompanying drawings, wherein like numbers reference like elements.

FIG. 1 is a perspective view illustrating a condition of a screen unit during use according to an embodiment.

FIG. 2 is a perspective view illustrating the condition of the screen unit during use.

FIG. 3 is a plan view schematically illustrating a condition of an expanding unit in the course of opening of the screen unit.

FIG. 4 is a perspective view illustrating a condition of the screen unit when the screen unit is not used.

FIG. 5 is a horizontal cross-sectional view illustrating a condition of the screen unit during use.

FIG. 6 is a horizontal cross-sectional view illustrating a condition of the screen unit when the screen unit is not used.

DESCRIPTION OF EXEMPLARY EMBODIMENT

An embodiment according to the invention is hereinafter described with reference to the drawings.

Embodiment

FIGS. 1 and 2 are perspective views illustrating a condition of a screen unit 1 during use according to this embodiment. FIG. 3 is a plan view schematically illustrating a condition of an expanding unit 30 in the course of opening of the screen unit 1. FIG. 4 is a perspective view illustrating a condition of the screen unit 1 when the screen unit 1 is not used. More specifically, FIG. 1 is a perspective view of the screen 1 during use on the front side as viewed from below. FIG. 2 is a perspective view of the screen unit 1 during use on the rear side as viewed from above. The dimensions and proportions of respective components shown in FIG. 3 are different from the actual ones. Each of FIGS. 1 through 4 shows a condition in which support feet 40 are accommodated in fixing portions 17 and 27. The structure and operation of the screen unit 1 are now explained in conjunction with FIGS. 1 through 4.

FIG. 1 and other figures are illustrated using an XYZ rectangular coordinate system. According to this coordinate system, the direction of the normal of the surface of a screen 5 corresponds to a Y direction (+Y direction: reflection surface side), the direction in which a first frame 10 extends corresponds to a Z direction, and the direction perpendicular to the Y direction and the Z direction corresponds to an X direction, as viewed in FIG. 1 as a reference figure. On the other hand, the direction of gravity corresponds to the downward direction, and the direction opposite to the direction of gravity corresponds to the upward direction, with respect to the direction of gravity as a reference direction.

The screen unit 1 in this embodiment is a reflection type screen unit, and includes the first frame 10 and a second frame 20 extending in parallel with each other, the screen 5, the expanding unit 30, and the support feet 40. The screen 5 extends between the first frame 10 and the second frame 20. The expanding unit 30 urges the first frame 10 and the second frame 20 in directions away from each other to maintain the positions of the first frame 10 and the second frame 20 with an arbitrary space provided therebetween (at arbitrary positions). The plural support feet 40 support the first frame 10 and the second frame 20 substantially in the vertical direction.

A first roll 11 and a second roll 21 (both are shown in FIGS. 5 and 6) around which the screen 5 is wound are accommodated in the first frame 10 and the second frame 20, respectively, in such a manner as to be freely rotatable. One end of the screen 5 is fixed to the first roll 11, while the other end of the screen 5 is fixed to the second roll 21. The details of the first roll 11 and the second roll 21 will be explained later.

The screen 5 is formed by a sheet-shaped screen base 51 having flexibility. In this embodiment, the screen base 51 is made of black vinyl chloride resin. The screen 5 further includes a white reflection film 52 disposed on the surface of the screen base 51. The screen 5 displays an image corresponding to projection light emitted from a projector (not shown) or other types of projection type display apparatus and reflected by the reflection film 52, as an image to be viewed from the +Y side (front side). The material of the screen 5 is not limited to vinyl chloride resin as in this embodiment but may be other materials as long as they are sheet-shaped and have sufficient flexibility.

Holder units 15 and 25 are provided on the first frame 10 and the second frame 20, respectively, at the centers of the outer surfaces thereof in the extending directions. The holder unit 15 provided on the first frame 10 has holders 15A and 15B disposed at the centers of the outer surfaces of the first frame 10 on the +Y side (front side) and the −Y side (rear side), respectively. Similarly, the holder unit 25 provided on the second frame 20 has holders 25A and 25B. The holder units 15 and 25 are portions to be held when the screen unit 1 is opened or closed. At the time of use, the screen unit 1 can be opened or closed by holding the holders 15A and 15B with one hand, and the holders 25A and 25B with other hand, for example.

To open the screen unit 1 (opening operation), both the first frame 10 and the second frame 20 are pulled in directions away from each other. On the other hand, to close the screen unit 1 (closing operation), both the first frame 10 and the second frame 20 are brought closer to each other.

Lock units 151 and 251 are further provided on the holder units 15 and 25. The lock units 151 and 251 are disposed on the front side and the rear side of the holder units 15 and 25 as mechanisms for fastening (locking) the first frame 10 and the second frame 20 without separation from each other while the screen unit 1 is being carried.

More specifically, the first frame 10 and the second frame 20 can be locked by engagement between hooks 151A formed at the tips of the lock units 151 on the front and rear sides and engaging portions 251A formed at the tips of the lock units 251 on the front and rear sides. This lock can be released by disengagement of the hooks 151A from the engaging portions 251A. A handle 29 to be held while the screen unit 1 is being carried is provided on the second frame 20 at the center of the outer surface thereof in the extending direction.

As illustrated in FIGS. 2 and 3, the expanding unit 30 has an arm unit 31 and an urging unit 35. The arm unit 31 has rod-shaped members each of which has a rectangular cross section. The arm unit 31 is constituted by a first arm 311, a second arm 312, a third arm 313, and a fourth arm 314. The first arm 311 and the second arm 312 of the arm unit 31 are connected to each other, while the third arm 313 and the fourth arm 314 of the arm unit 31 are connected to each other. The arm unit 31 is joined to the first frame 10 and the second frame 20 in the shape of a pantograph.

One end 311 a of the first arm 311 is fixed to the lower end of the first frame 10 in such a manner as to be freely rotatable. The other end 311 b of the first arm 311 and one end 312 a of the second arm 312 are fixed to each other in such a manner as to be freely rotatable. The other end 312 b of the second arm 312 is fixed to the substantially center of the second frame 20 in such a manner as to be freely rotatable.

Similarly, one end 313 a of the third arm 313 is fixed to the upper end of the first frame 10 in such a manner as to be freely rotatable. The other end 313 b of the third arm 313 and one end 314 a of the fourth arm 314 are fixed to each other in such a manner as to be freely rotatable. The other end 314 b of the fourth arm 314 is fixed to the substantially center of the second frame 20 in such a manner as to be freely rotatable.

As illustrated in FIG. 3, the urging unit 35 includes a first urging member 351, a second urging member 352, and a tape-shaped member 353. The first urging member 351 and the second urging member 352 fasten both ends of the tape-shaped member 353, and urge the tape-shaped member 353 in the winding direction of the tape-shaped member 353.

The first urging member 351 is provided in such a condition as to be sandwiched between the other end 311 b of the first arm 311 and the one end 312 a of the second arm 312. Similarly, the second urging member 352 is provided in such a condition as to be sandwiched between the other end 313 b of the third arm 313 and the one end 314 a of the fourth arm 314.

As illustrated in FIG. 3, the expanding unit 30 in the course of opening of the screen unit 1 receives an urging force (force for winding the tape-shaped member 353) from the urging unit 35 in such a direction as to bring the other end 311 b of the first arm 311 and the other end 313 b of the third arm 313 (or the one end 312 a of the second arm 312 and the one end 314 a of the fourth arm 314) closer to each other. This urging force allows the expanding unit 30 to shift the first frame 10 and the second frame 20 in directions away from each other (direction of expanding the screen 5).

The support feet 40 are provided such that one foot is disposed at each position of the lower ends of the first frame 10 and the second frame 20 on the front side and the rear side (four in total). Plate-shaped foot main bodies 41 of the support feet 40 are attached to and accommodated in the fixing portions 17 and 27 recessed in the first frame 10 and the second frame 20. During use of the screen unit 1, the foot main bodies 41 are laid to project in the Y direction from the first frame 10 and the second frame 20 so that the first frame 10 and the second frame 20 can be maintained substantially in the vertical position. When the screen unit 1 is not used, the foot main bodies 41 are accommodated in the fixing portions 17 and 27.

FIG. 5 is a horizontal cross-sectional view illustrating a condition of the screen unit 1 during use. FIG. 6 is a horizontal cross-sectional view of the screen unit 1 when the screen unit 1 is not used. The structure and operation of the first roll 11 and the second roll 21 around which the screen unit 5 is wound are now explained with reference to FIGS. 5 and 6.

As illustrated in FIGS. 5 and 6, the first roll 11 and the second roll 21 around which the screen 5 is wound are accommodated in the first frame 10 and the second frame 20 in the extending directions thereof in such a manner as to be rotatable around rotation axes A and B.

One end of the screen 5 is fixed to the first roll 11, while the other end of the screen 5 is fixed to the second roll 21. Each of the first roll 11 and the second roll 21 has a spring which urges the corresponding roll 11 or 21 in the winding direction. This mechanism is not specifically shown in the figure. In FIG. 6, the direction and the general strength of the urging force of the first roll 11 is indicated by an arrow C, while the direction and the general strength of the urging force of the second roll 21 is indicated by an arrow D.

According to this embodiment, the strength of the urging force of the first roll 11 is different from the strength of the urging force of the second roll 21. More specifically, the approximate strength ratio of the urging force of the first roll 11 to the urging force of the second roll 21 is set at 9:1 which establishes a preferable relationship between the forces of the first roll 11 and the second roll 21 for mutual corrections of twist produced on the screen 5 at the time of winding.

For using the screen unit 1, the support feet 40 (foot main bodies 41) are initially rotated to such positions as to be substantially perpendicular to the first frame 10 and the second frame 21. Then, the first frame 10 and the second frame 20 are pulled in directions away from each other (opening operation) by using the holder units 15 and 25. As a result, the screen 5 is drawn from the first roll 11 and the second roll 21 while resisting the respective urging forces of the first roll 11 and the second roll 21.

In accordance with the expansion of the screen 5, the expanding unit 30 gives a predetermined urging force to each of the first frame 10 and the second frame 20 in directions away from each other. The urging force of the expanding unit 30 is determined based on the strengths of the urging forces of the first roll 11 and the second roll 21. Thus, an arbitrary length can be set as the space between the first frame 10 and the second frame 20.

When the screen 5 is further drawn out, the pair of the second arm 312 and the fourth arm 314 and the pair of the first arm 311 and the third arm 313 of the expanding unit 30 are bought into a condition of pulling against each other as illustrated in FIG. 2. In this condition, the urging force of the expanding unit 30 (urging force of the urging unit 35) becomes larger than the urging forces of the first roll 11 and the second roll 21. This condition corresponds to the maximum expansion of the screen 5.

For storing the screen 5, the first frame 10 and the second frame 20 are initially pressed in directions closer to each other (closing operation) by using the holder units 15 and 25. This step releases the condition in which the pair of the first arm 311 and the third arm 313 and the pair of the second arm 312 and the fourth arm 314 of the expanding unit 30 pull each other. As a result, the arm unit 31 (first arm 311, second arm 312, third arm 313, and fourth arm 314) is folded within the second frame 20 while resisting the urging force of the expanding unit 30.

Then, the screen 5 is wound around the first roll 11 and the second roll 21 in accordance with the respective urging forces of the first and second rolls 11 and 21. In this embodiment, the strengths ratio of the first roll 11 to the second roll 21 is set at 9:1. Thus, the second roll 21 having the smaller urging force follows the rotation of the first roll 11 having the larger urging force.

For winding the screen 5, the first roll 11 to which one end of the screen 5 is fixed and the second roll 21 to which the other end of the screen 5 is fixed wind the screen 5 by the respective urging forces of the first and second rolls 11 and 21 acting in the respective winding directions while urging the screen 5 in the directions toward both the ends of the screen 5. The urging forces applied by the first and second rolls 11 and 21 to the screen 5 in the directions toward the ends of the screen 5 provide mutual corrections of twist of the screen 5 when the screen 5 is wound with twist.

Then, the first frame 10 and the second frame 20 come into contact with each other, and into the locked condition as illustrated in FIG. 6. Finally, the support feet 40 (foot main bodies 41) are rotated to be accommodated in the fixing portions 17 and 27 of the first frame 10 and the second frame 20 as a step for completion of the storing process of the screen 5 (see FIG. 4).

As illustrated in FIG. 6, an engaging portion 16 and an engaging portion 26 are provided on the first frame 10 and the second frame 20, respectively, on the inner end surfaces of the first and second frames 10 and 20 as the contact positions with each other. The engaging portion 16 has an engaging piece 16A provided on the front side, and an engaging piece 16B provided on the rear side. The engaging portion 26 has an engaging piece 26A provided on the front side, and an engaging piece 26B provided on the rear side. Under the condition of the engagements between the engaging piece 16A and the engaging piece 26A and between the engaging piece 16B and the engaging piece 26B, the lock units 151 and 251 lock up the first frame 10 and the second frame 20 together without shift toward the front side or the rear side.

Roll diameters of the first roll 11 and the second roll 21, and arm fixing portions 18 and 28 for fixing the expanding unit 30 are now explained with reference to FIGS. 3, 5 and 6.

The one end 311 a of the first arm 311 of the arm unit 31 constituting the expanding unit 30 shown in FIG. 3 is fixed to the lower end of the first frame 10 in such a manner as to be freely rotatable as explained above. Similarly, the one end 313 a of the third arm 313 is fixed to the upper end of the first frame 10 in such a manner as to be freely rotatable as explained above. More specifically, the one ends 311 a and 313 a are fixed to the arm fixing portion 18 provided on the first frame 10 in such a manner as to be freely rotatable as illustrated in FIGS. 5 and 6.

On the other hand, the other end 312 b of the second arm 312 shown in FIG. 3 is fixed to approximately the center of the second frame 20 in such a manner as to be freely rotatable as explained above. Similarly, the other end 314 b of the fourth arm 314 is fixed to approximately the center of the second frame 20 in such a manner as to be freely rotatable as explained above. More specifically, the other ends 312 b and 314 b are fixed to the arm fixing portion 28 provided on the second frame 20 in such a manner as to be freely rotatable as illustrated in FIGS. 5 and 6.

When the screen 5 is stored, the arm unit 31 is folded within the second frame 20 as illustrated in FIG. 6. More specifically, the arm unit 31 is folded on the rear side of the second roll 21 provided within the second frame 20. FIG. 6 shows a crosshatched expanding unit storage area E as an area within which the arm unit 31 is folded and stored.

As can be seen from FIG. 6, a roll diameter R2 of the second roll 21 is different from a roll diameter R1 of the first roll 11 in this embodiment. More specifically, the roll diameter R2 of the second roll 21 is smaller than the roll diameter R1 of the first roll 11. According to this embodiment, therefore, almost all parts of the arm unit 31 can be stored within the second frame 20 when folded on the rear side of the second roll 21 having the smaller roll diameter, which decreases the size of the screen unit 1.

This embodiment can offer the following advantages.

According to the screen unit 1 in this embodiment, the first roll 11 having the urging force in the winding direction is provided in the first frame 10 in such a manner as to be freely rotatable, and the second roll 21 having the urging force in the winding direction is provided in the second frame 20 in such a manner as to be freely rotatable. One end of the screen 5 is fixed to the first roll 11, and the other end of the screen 5 is fixed to the second roll 21. According to this structure, when the screen 5 is wound, the first roll 11 and the second roll 21 wind the screen 5 while urging the screen 5 in the directions toward both the ends of the screen 5. In this case, twist of the screen 5 can be mutually corrected by the first roll 11 and the second roll 21 when the screen 5 is wound with twist. Accordingly, the screen unit 1 can reduce distortion or wrinkle produced on the surface of the screen 5 during use by preventing twist produced at the time of storage of the screen 5.

According to the screen unit 1 in this embodiment, the strength ratio of the urging force of the first roll 11 to the urging force of the second roll 21 is set at approximately 9:1 which establishes a preferable strength relationship. For winding the screen 5, the second roll 21 having the small urging force follows the rotation of the first roll 11 having the large urging force. In this case, twist of the screen 5 produced when the screen 5 is wound around the first roll 11 having the large urging force can be corrected by the second roll 21 having the smaller urging force and following the rotation of the first roll 11 for winding the screen 5. Accordingly, the screen unit 1 can reduce distortion or wrinkle produced on the surface of the screen 5 during use.

According to the screen unit 1 in this embodiment, the roll diameter R2 of the second roll 21 is smaller than the roll diameter R1 of the first roll 11. In this case, the expanding unit 30 can be folded (stored) on the rear side of the second roll 21 within the second frame 20 on which the second roll 21 is disposed. Accordingly, the size of the screen unit 1 can be reduced.

According to the screen unit 1 in this embodiment, the urging force of the second roll 21 is smaller than the urging force of the first roll 11. In this case, the volume of the screen 5 wound around the second roll 21 becomes smaller as well. Accordingly, a sufficient space for storing the folded expanding unit 30 can be secured on the rear side of the second roll 21, which further decreases the size of the screen unit 1.

The invention is not limited to the embodiment described herein but includes various modifications, improvements and the like without departing from the scope of the invention. For example, the following changes may be made.

According to the screen unit 1 in this embodiment, the strength of the urging force of the first roll 11 is different from the strength of the urging force of the second roll 21 at the ratio of approximately 9:1. However, the ratio is not limited to this specific ratio but may be any ratio as long as the two strengths of the forces differ from each other. Therefore, an arbitrary ratio may be determined based on the structure and the like of the screen unit.

According to the screen unit 1 in this embodiment, the strength ratio of the urging force of the first roll 11 to the urging force of the second roll 21 is set at approximately 9:1. However, the strengths of the urging forces may be substantially equivalent.

While the screen unit 1 in this embodiment is a portable screen unit, the invention is applicable to a stationary screen unit (both manual and automatic) which is fixed to a wall, a ceiling, a floor or the like. This type of screen unit can provide advantages similar to those of the screen unit 1. 

What is claimed is:
 1. A screen unit comprising: a first frame and a second frame which extend in parallel with each other; a first roll provided in the first frame in such a manner as to be freely rotatable and having an urging force in the winding direction of the first roll; a second roll provided in the second frame in such a manner as to be freely rotatable and having an urging force in the winding direction of the second roll; and a screen which has one end fixed to the first roll and the other end fixed to the second roll.
 2. The screen unit according to claim 1, wherein the urging force of the first roll is different from the urging force of the second roll.
 3. The screen unit according to claim 2, wherein the strength ratio of the urging force of the first roll to the urging force of the second roll is set at approximately 9:1.
 4. The screen unit according to claim 1, wherein the roll diameter of the first roll is different from the roll diameter of the second roll. 